Ni/SiO₂Catalyst With Support Treated By Dielectric Barrier Discharge Plasma

As one of the most promising ways of converting and utilizing natural gas,carbon dioxide reforming of methane is of importance to reliefing the energy crisiscaused by running out of oil and utilizing CO2in order to mitigate the greenhouseeffect. In addition, syngas made in CH4-CO2reforming has a low H2/CO ratio, and isideal feedstock for synthesis of chemicals with high value. It is the key forpopularizing CH4-CO2reforming to inhibit carbon deposition on the nickel catalyst inthe reaction and to enhance the stability of catalystIn the paper, Ni/SiO2catalyst was prepared using SiO2treated by dielectricbarrier discharge plasma before impregnation, recorded as Ni/(SiO2-P). The catalystprepared using non-treated SiO2is recorded as Ni/SiO2-N. Compared with Ni/SiO2-N,Ni(SiO2-P) has stronger interaction between Ni and SiO2, higher dispersion of Ni,smaller Ni particles, and narrower particle size distribution. In CH4-CO2reforming,Ni/(SiO2-P) shows higher activity, selectivity and stability. After reaction at650℃for5h, the conversion of CH4on Ni/(SiO2-P) is approximately6%higher than onNi/SiO2-N. after reaction at700℃for6h, the conversion of CH4on Ni/(SiO2-P) wasonly about3%lower than at the beginning of reaction. By the analysis of catalystsafter reaction, it is found that compared with Ni/SiO2-N, the burning peaks of carbondeposited on Ni/(SiO2-P) shift to lower temperature. That implies that carbondeposited on Ni/(SiO2-P) is more active, and easier to react with CO2into gas in thereforming reaction, which inhibits the accumulation and covering of carbon depositedon catalyst and enhances the stability of catalyst. Ni/(SiO2-P) also shows higheractivity in methanation of carbon monoxide, and enhanced resistance to sintering aswell. After the high temperature reaction at700℃for6h, Ni/(SiO2-P) was still moreactive than Ni/SiO2-N.